Hydraulic power lift



May 5, 1936. E. A. JOHNSTON HYDRAULIC POWER LIFT Filed May 22, 1935 '4 Sheets-Sheet 1 WNW May 5, 1936. E. A. JOHNSTON HYDRAULIC POWER LIFT Filed May 22, 1935 4 Sheets-Sheet 2 May 5, 1936. E. A. JOHNSTON HYDRAULIC POWER LIFT 4 Sheet-Sheet 5' Filed May 22, 1935 IYLUGVZiO? E0Zzzrar rfoiznsion/ 39 /5% I k 1 W \ZZ.

May 5, 1936- E; A. JOHNSTON HYDRAULIC POWER LIFT Filed May 22, 1935 4 Sheets-Sheet 4 Invenior ion JoZu/ar //z Patented May 5, 1936 nrnmwuc rowan 1m- Edward A. Johnston, Chicago, 11]., asaignor to International Harvester Company, a corporation of New Jersey Application May 22, 1935, Serial No. 22,888

Claims.

The present invention relates generally to farm tractors for propelling, carrying, and operating agricultural implements, and more specifically to power operated lifting devices.

The fundamental object of the invention is to provide improved mechanism mounted on the tractor driven by power derived from the engine for lifting, lowering or otherwise adjusting implements, such as plows-and cultivators, attached to or operated by the tractor.

More specifically, one object of the invention is to provide a power lift mechanism which is hydraulically actuated. Another object subsidiary to said object is to provide an improved and simplified two-way acting hydraulic mechanism.

Another object is to provide a hydraulic mechanism which may be constructed to move an operating lifting shaft through substantially more than a half revolution, whereby the crank may be connected to lifting members to move past dead center in either of two positions.

Another object is to provide a hydi'aulic lifting mechanism particularly adapted to the oscillation of a crank or rockshaft for use in lifting implements.

The above objects and others, which will be apparent from the detailed description to follow, are accomplished by the mounting of a hydraulic mechanism of a construction which may be designated as a vane type, the vane being mounted in a chamber for oscillation through an angle of substantially more than 180 degrees. The lifting member in the form of a crank or rock-shaft is connected to and moved by the vane of the mechanism. A hydraulic pump is mounted on the tractor in any suitable position for supplying operating liquid to the hydraulic mechanism. A suitable control valve and properly located conduits are provided for delivering the high pressure liquid to either side of the vane and for allowing the escape of liquid simultaneously from the other side of the vane. In order to provide a mechanism in which the supply of high pressure liquid is rendered ineffective after the vane has. completed its stroke, valve means are utilized which are automatically operable by movement of the vane into its respective positions of rest at the ends of its strokes in each direction.

In the drawings,

Figure l is a side elevation of a tractor with one wheel removed and with a portion of the transmission casing being broken away to show the installation of' an'd driving mechanism for the liquid pump of the hydraulic-lift, a portion of a directly connected implement being shown at the rear of the tractor and a forwardly extending lifting beam being shown extending toward the front of the tractor; I

Figure 2 is a plan view of the rear end oi. the tractor shown in Figure 1, particularly showing 5 the power lift mechanism;

Figure 3 is a rear view of the rear end portion of the tractor shown in Figure 1, and of the power lift mechanism mounted thereabove;

Figure 4 is an enlarged plan view of the central 1'0 portion of the power lift mechanism shown in Figure 2 with the top of the valve chamber in horizontal cross-section and with a portion of the casing broken away to show the liquid chambers and the vane or piston chamber of. the hydraulic mechanism;

Figure 5 is a vertical section taken on the line 55 of Figure 4;

Figure 6 is a vertical section along the line 6-6 of Figure 4; i 20 Figure 7 is a vertical section taken on the line 1-1 of Figure 4; and,

Figure 8 is an enlarged detail, showing the vane of the hydraulic lift, the two lifting shafts, and the connection between the shafts, including the supporting means for the vane.

Only-a portion of a tractor has been shown, as such tractor may be of any of the conventional types used for operating farm implements. The tractor illustrated shows diagrammatically a frame It! connected to a rearwardly located casing I I, which houses the transmission and differential of the tractor driving mechanism. The rear end ii of an engine is shown and other parts of the tractor, such as the gasoline tank I! and the steering wheel I 4. The operator's seat I5 is connected at a forward point in order to provide sumcient space for mounting the power lift mechanism directly over the rear axle of. the tractor.

Laterally extending axle housings l6, rigidly 40 secured to the sides of the housing II at the rear thereof, form, lateral supports for the driving axles. H on which the traction wheels l8 are mounted. Suitable flanges IS on the housings l6 provide means for attaching supports for 5 implements, such for example'as the support- 7 ing bars 2| to which rearwardiy extendingimplement beams 22 are connected. Said beams are illustrated as carrying spring shanks of a type on which cultivator shovels may be convention-- ally mounted. Rearwardly extending supporting bars 23 are also shown connected to the flanges l9.' At the rear end of each of said bars a bell-crank lever 24 provides means for lifting and lowering the implement beam 22 through a lifting link 25.

Connections between the bell-crank member 24 and the power lifting device will be later described in connection with said device.

, The housing I of the tractor shown is constructed with an open top over which a coverplate is normally secured. For mounting the power lift device constituting this invention, said cover-plate is removed and a specially constructed cover-plate 26 is substituted therefor. Said cover-plate, which is preferably constructed from a casting, carries a forward bracket on which the operators seat I 5 is mounted. At the rear of the casting, a. base 21 is formed, on the upper surface of which the power lift casing 28 is securely fastened by a plurality of cap-screws, as illustrated.

The power lift casing 28 is cored to form at the rear end a high pressure fluid inlet cham ber 29 to which liquid under pressure is supplied by a conduit 38 connected with a pump casing 3|. The pump casing 3| is secured to the rear of the casing ll of the tractor, being substituted for a cover-plate regularly supplied over a comparatively small opening at the rear of the housing. Said pump casing includes a gear pump consisting of gears 32, one of which is mounted on a shaft 33 extending, through a projecting boss 34 into the interior of the hous- By means of a train of gearing of conventional design, said shaft is driven from the power take-off shaft 35 extending longitudinally of the tractor at the bottom of the housing The only change required in the usual power take-off shaft is the addition of a driving gear 36, which is keyed on the shaft for engagement with the train of gears for driving the pump shaft 23. The pump casing 3| and the gears carried thereby are of a size and are so mounted that the entire unit may be removed through the rear opening in the housing I I, over which the casing is secured. The power'take-oif shaft 35 may be utilized with the pump in place, or removed.

A low pressure return conduit 31 connects the low pressure side of the pump with a reservoir 38 formed in the casing 28.. The details of the pump have not been shown, as it is of any well known conventional construction, being of a capacity suflicient to deliver liquid in the quantity and at the pressure required for operating the lifting device.

A substantially semi-cylindrical chamber 39 is formed at one side of the casing 28, being open at one side for assembling the component parts into position. A cover-plate 40 is formed to fit over the open side and to form a liquid-tight joint therewith. Said cover-plate also carries a laterally extending sleeve 4|, through which an operating shaft 42 extends. An aligned operating shaft 43 extends through a bore formed in the casing 28 and a laterally extending sleeve. The portions ofthe shafts within the chamber 38 are best shown in Figure 7. Said shafts are formed with enlarged cylindrical end portions.

which are secured together against rotation by pins 44, as shown 'in the dotted lines in Figures 4, 7 and 8.

A radial slot 45 is formed in the cylindrical end portion of the shaft 43. Said slot forms a means for slidably mounting the vane 46, which is substantially rectangular in shape except for a cut-off corner within the slot '45 to correspond to an arcuate end wall of said slot. A compression spring 41, seated in aligned bores in the vane 46 and in the enlarged end portion of the shaft 43, urges thevane 46 radially out wardly, whereby it is maintained in contact with the cylindrical wall of the chamber 39. The contacting end of the vane, as well 'as the edges and faces within the slot 45, are closely and accurately fitted to provide for a substantially fluid-tight seal between the two compartments formed on opposite sides of the vane.

At one portion of the upper side of the casing 28 a substantially circular, flat face 48 is formed to provide a seat for a valve casing '49. Said casing houses a rotatable valve member 5|], which is operable from a shaft 5| by a non-rotatable connection between the shaft and the valve member. An operating handle 52 is non-rotatably secured to the upper end of the shaft 5| outside the casing. Suitable packing may be provided for preventing the escape of liquid around the A pressure spring 53 is positioned to abut the valve member 50 and hold it against the seat 48.

To provide means for balancing the valve memsitioned over said passage-way. A second passage-way 59 communicating with the seat 48; on

which the valve member is mounted, extends vertically downwardly and through a cored passage 60 at the base of the housing 28, terminating, as shown in Figure 6, adjacent one end of the 'semiannular chamber 39 in which the vane 46 oscillates.

It will be understood that, with the valve member 50 the position shown in Figure 4,

fluid under pressure is conducted through the passage-way 58, the recess 51, the passage-way 59 and the passage-way 69 into the chamber 39. If the vane is in the dotted position shown in Figure 7, pressure is then applied to the vane, rotating it about its mounting axis in a clockwise direction. At the same time, liquid at the other side of the vane escapes through a passage-- way 6| similar to the passage-way 60, which communicates with the chamber 39 in a corresponding position at its other end. As shown in Figure 5 and in dotted lines in Figure 4, the pas sage-way 6|, which is cored in the base of the housing 28, communicates with a vertical conduit 62 communicating with the seat 48 over which thevalve member 59 is mounted. With the valve member in the position shown in Figure 4, fluid escaping through the vertical conduit 62 passes through the recess 56 and downwardly through an opening 63 communicating with the reservoir 38. This illustrates a complete circuit of the liquid during the lifting operation.

and designated by numerals was made with simultaneous explanation of the operation of the device of which said elements described are parts.

There is another important feature which will the reservoir 38. Liquid thereafter supplied through the conduit Ell-considering the vane as being in the position shown in Figure "I-is bypassed back into the reservoir through the conduit 66, the bore 61 and the by-pass opening 68. A corresponding conduit 66 and a bore 61 are formed at the other side of the vane to similarly by-pass liquid under pressure supplied through the passage-way 6| when the vane'is in the dotted position indicated in Figure 7. It will be understood that, by the provision of a by-pass arrangement as described, it is only necessary for the operator to shift the valve into either one of the two positions, there being no provision for a neutral position. The vane is then rotated to its end position, after which liquid is by-passed with no appreciable back pressure. When it is desired to rotate the lifting,

shafts 43 and 44 in the other direction, the valve member 56 is shifted degrees, whereby the vane 46 is moved angularly to its other end position.

It will be noted that substantially more than 180degrees angular movement has been provided for'the vane 46 in the annular chamber'39. This provision has been made particularly for use of the device in connection with the lifting of field implements. Referring to Figure l, the projecting end' of the shaft 43 visible in that figure carries a lifting member 69 which is provided with a plurality of circumferentially spaced openings 10. A crank pin ll mounted in one of these openings forms a pivotal support for a rearwardly extending lifting link I2 and a forwardly extending lifting link 13. The shaft 42 is provided with the same lifting connections. It will be noted that with the implements lifted as represented in this figure ofthe drawings, the pin H is past dead center with respect to the axis of the lifting shaft 43. As the forward lifting member 13 is a compression memberand as the rear lifting link ,12 is a tension member, the weight of the implements acts to hold the lifting device locked in this past dead center position. When the vane is oscillated to its other extreme position, the pin II will be past dead center at the other side. of the axis of the shaft 43. In this position, with the implements lowered, the member 12 becomes a compression member and the member I3 becomes a tension member. It is;

therefore, to be understood that in this position the pressure of the implements also tends to hold the lifting device locked in its over-dead-center position. This description is given as one embodiment in which the inherent property of applicants device in permitting over-deadcenter in two positions may be utilized to great advantage. In either of these positions the vane is abutting the stops provided and there is no tendency for the lifting device to leave its position. Moreover, at the end of the stroke in each direction the vane is moved by the force of the lifting connections to complete its stroke and to i putthe byepass communications into operation, whereby pressure is released. Due to this principle of operation there is practically no back pressure exerted on the pumping system, requiring substantially no power and resulting in very little wear upon the pump gears or upon the chain of the drivinggears therefor.

Although applicant has shown and described his improved hydraulic lifting device as'located in a preferred position on a tractor and as operating lifting means for implements located in certain" positions, it is to be understood that he claims as his invention all modifications in the construction of the lifting mechanism, its location on a tractor, and its use in connection with different types of lifting connections and different implements which may be covered by the appended claims.

What is claimed is: a

1. A power lift device for tractors comprising,

in combination with a tractor and an implement connected thereto, a transverse rock-shaft mounted on the tractor, lifting connections between the rock-shaft and the implement, a lifting shaft mounted on the tractor spaced longitudinally from the rock-shaft, a liftinglever on the rockshaft, a lifting crank on the lifting shaft, a lifting member connecting said crank and said lever,-

a casing into whichthe lifting shaft extends, a

vane secured to said shaft within the casing, and means to apply pressure to either side of the'vane whereby the lifting shaft may be rotated in opposite angular directions. 7

2. A power lift device for tractors comprising, in combination with a tractor and an implement connected thereto, a transverse rock-shaft mounted on the tractor, lifting connections between the rock-shaft and the implement, a lifting shaft mounted on the tractor spaced longitudinally from the rock-shaft, a lifting lever on the rock-shaft, alifting crank on the lifting shaft; a lifting member connecting saidjcrank and said lever, a casing' into which the lifting shaft extends, a vane secured to said shaft within the casing, and means"- to apply pressure to either side of the vane" whereby the lifting shaft may be rotated in opposite angular directions, said means being ef-" fective to move the vane substantially more than degrees in each angular direction.

3. A power lift device for tractors comprising, in combination with a tractor and an implement connected thereto, a transverse rock-shaft mounted on the tractor, lifting connections between the rock-shaft and the implement, a lifting shaft mounted on the tractor spaced longitudinally from the rock-shaft, a lifting lever on the rockshaft, a lifting crank on the lifting shaft, alifting member connecting said crank and said lever, a easing into which the lifting shaft extends, a

-vane secured to said shaft within the casing, and

means to apply pressure to either side of the vane wherebythe lifting shaft may be rotated in opposite angular directions, said means being effective to move the vane substantially more than 180 degrees in each angular direction, the lifting crank being positioned relative to the vane to be moved past dead center with respect-to a center line 7 from the axis of the lifting shaft to the connection point of the lifting member with the lifting lever on the rockshaft.

4. A power lift device for'tractors comprising, in combination with a tractor and an implement position to reduce the application of pressure thereto.

5. A power lift device for tractors comprising,

' in combination with a tractor and an implement connected thereto, a transverse rock-shaft mounted on the tractor, lifting connections between the rock-shaft and the implement, a lifting shaft mounted on the tractor spaced longitudinally from the rockshaft, a lifting lever on the rockshaft, a lifting crank on the lifting shaft, a lifting member connecting said crank and said lever, a easing into which the lifting shaft extends, a vane secured to said shaft within the casing, means for supplying fluid under pressure to either side of the vane, and means operable by movement of the vane at a predetermined angular position to reduce the application of fluid pressure thereto and to hold the vane in that position. 6. In a tractor having a housing at the rear thereof containing driving gearing, said housing having an opening normally closedby a coverplate and, in combination therewith; a power lift casing secured to the housing over said opening, a transverse lifting shaft extending into said casing, a hydraulic device in the casing connected to the lifting shaft for transmitting angular movement to the shaft, a liquid pump mounted on the housing adapted to be driven by the gearing within the housing, and means for conducting fluid under pressure from the pump to the easing for actuating the hydraulic device to rotate the lifting shaft in either direction.

7. In a tractor having a housing at the rear thereof containing driving gearing, said housing having an opening normally closed by a coverplate and, in combination therewith; a power lift casing secured to the housing over said opening, a transverse lifting shaft extending into said casing, a hydraulic device in the casing connected to the lifting shaft for transmitting angular movement to the shaft in either direction, a liquid pump mounted on the housing adapted to be driven by the gearing within the housing, and means for conducting fluid under pressure from the pump to the casing for actuating the hydraulic device.

8. In a tractor having a housing at the rear 7 thereof containing driving gearing, said housing having an opening normally closed by a cover-plate and, in combination therewith; a power lift casing secured to the housing over said opening, a transverse lifting shaft extending into said casing, a hydraulic device in the casing including a vane directly connected tothe lifting shaft for transmitting angular movement to the shaft in either direction, a liquid pump mounted on the housing adapted to be driven by the gearing within the housing, and means for conducting fluid under pressure from the pump to the casing for actuating the hydraulic device.

9. In a tractor having a housing at the rear thereof containing driving gearing, said housing having an opening normally closed by a coverlindrical chamber,

tractor connected plate and, in combination therewith, a power lift casing secured to the housing over said opening, a transverse lifting shaft extending into said casing. a hydraulic device in the casing connected to the lifting shaft for transmitting angular movement to the shaft, a liquid pump mounted on the housing adaptedto be driven by the gearing within the housing, and means for conducting fluid under pressure from the pump to the casing for actuating the hydraulic device to rotate the lifting shaft in either direction, said means being operative to supply fluid continuously and said hydraulic device including means operative to render the device ineffective when a predetermined location is reached in the angular movement of the shaft.

10. A hydraulically operated power lift for tractor connected implements comprising a housing mounted on the tractor, a transverse shaft extending through'said housing, means for connecting a lifting member to said shaft outside the housing, a substantially semicylindrical chamber formed in the housing around the shaft, a vane secured to said shaft for angular movement therewith in the chamber, means for supplying fluid under pressure to the semicylindrical. chamber at each side of the vane adjacent the bottom of the chamber, whereby the vane may be moved in opposite angular directions, and by-pass means operated by movement of the vane to bypass fluid when the vane has reached its maximum position in either angular direction.

11. A hydraulically operated power lift for tractor connected implements comprising a housing mounted at the rear of the tractor, a transverse shaft extending through said housing, means for connecting a lifting member to said shaft outside the housing, a substantially semicylindrical chamber formed in the housing around the shaft, a vane secured to said shaft for angular movement therewith and fitted in a substantially fluid-tight manner in the semicya liquid pump mounted on the tractor and driven from the tractor engine, a valve chamber mounted on the tractor, fluid conduits connecting the pump, the 'valve chamber and the housing, two of said conduits being formed to communicate with the semicylindrical chamber at each side of the bottom of the chamber, said ated to deliver fluid under pressure to either of said conduits whereby the vane may be moved in opposite angular directions, and by-pass means operated by movement of the vane to by-p ass fluid when the vane has reached its maximum position in either angular direction.

12. A hydraulically operated power lift for implements comprising I a housing mounted at the rear of the tractor, a

- transverse shaft extending through said housing, means for connecting a lifting member to said shaft outside the housing, a chamber formed in the housing as a portion of a cylinder in a substantially fluid-tight manner therein, means for supplying fluid under pressure to the chamber at each side of the vane whereby the vane may be moved in opposite angular directons, and by-pass means operated by movement of the vane to by-pas's fluid when the vane has reached its maximum position in either angular direction.

extends, a vane secured to said shaft within the tractor engine, a valve chamber mounted on the tractor, fluid conduits connecting the pump, the valve chamber and the housing, two of said conduits being formed to communicate with the semicylindrical chamber at each side of the vane adjacent the bottom of the chamber, said valve being operated to deliver fluid under pressure to either of said conduits whereby the vane may be moved in opposite angular directions, and by-pass means operated by movement of the vane to by-pass fluid when the vane has reached its maximum position in either an lar direction.

14. A hydraulically operated power lift for tractor .connected implements comprising, in combination with a tractor, a housing mounted on the tractor, a shaft extending into said housing, means for connecting a lifting member to said shaft outside the housing, a substantially semicylindrical chamber formed in the housing around the shaft, a vane secured to said shaft for angular movement therewith and fltted in asubstantially fluid-tight manner in the chamber, a liquid pump mounted on the tractor and driven from the tractor engine, a valve chamber mounted on the tractor, fluid conduits connecting the pump, the valve chamber and the housing, one of said conduits being formed to communicate with the semicylindrical chamber at each side of the vane adjacent the bottom of the chamber, said valve being operated to deliver fluid under pressure to either side of the vane, and by-pass means operated by movement of the vane to bypass fluid when the vane has reached its maximum position in either angular direction.

15. A power lift device for tractors comprising, in combination with a tractor and an implement connected thereto, a rockshaft mounted on the tractor, lifting connections between the rockshaft and the implement, a lifting shaft mounted on the tractor spaced from the rockshaft, a lifting lever on the rockshaft, a lifting crank on the lifting shaft, a lifting member connecting said crank and said lever, a'casing into which the lifting shaftextends, a vane secured to said shaft within the casing, and means to apply fluid pressure against the vane.

16.- A power lift device for tractors comprising, in combination with a tractor and an implement.

connected thereto, a rockshaft mounted on the.

tractor, lifting connections between the rockshaft and the implement, a lifting shaft mounted-on the tractor spaced from the rockshaft, a lifting lever on the rockshaft, a lifting crank on the lifting shaft, a lifting member connecting said crank and said lever, a easing into which the lifting shaft casing for an angular movement of substantially more than and means to apply fluidpressure against either side of the vane whereby the lifting shaft may be rotated in opposite angular-directions, said means being effective to move the vane substantially more than 180 in each angular direction.

17. A power lift device for tractors comprising, in combination with a tractor and an implement connected thereto, a rockshaft mounted on the tractor, lifting connections between the rockshaft and the implement, a lifting shaft mounted on the tractor spaced from the rockshaft, a lifting lever on the rockshaft, alifting crank on the lifting shaft, a lifting member connecting said crank and said lever, a easing into which the lifting shaft extends, a vane secured to said shaft within the casing, and means to apply pressure to either side of' the vane whereby the lifting shaft may be rotated in opposite angular directions, said means being effective to move the vane substantially more than 180 in each angular direction, the lifting crank being positioned relative to the vane to be moved past dead center with respect to a center line fromthe axis of the lifting shaft to the connection point of the lifting member with the lifting lever on the rockshaft.

18. A power lift device for tractors comprising, in combination with a tractor and an implement connected thereto, a lifting shaft mounted on the tractor, a lifting crank on the lifting shaft,

means for connecting said crank to the imple-- ment, a easing into which the lifting shaft extends, a vane secured to said shaft within the easing, means for supplying fluid under pressure to either side of the vane, and means ope able by movement of the vane at apredetermined angular position to reduce the supply of fluid-thereto.

19. A power lift device for-tractors comprising,

in combination with a tractor and an implement.

tor connected implements comprising a housing mounted on the tractor, a shaft extending through said housing, means for connecting a lifting member to said shaft outside the housing, a, substantially semicylindrical chamber formed in-the hous ing around the shaft, a vane secured to said shaft for angular movement therewith in the chamber,

. means for supplying fluid under pressure to the semicylindrical chamber at one side of the vane adjacent the bottom of the chamber, whereby the vane may be moved in an angular direction, and by-pass means operated by movement of the vane to by-pass fluid whenthe vane has reached its maximum position.

' EDWARD A. JOHNSTON. 

